By Mark Kinver
Science and environment reporter, BBC News
An injured pale-phase honey buzzard had to be put down by a vet
Conservation groups have criticised Malta for failing to stop "rogue" hunters killing protected bird species.
During a two-week monitoring programme, BirdLife Malta said it treated 17 birds of prey suffering from gunshot wounds.
Large numbers of birds pass over the Mediterranean island, which lies along a major migratory route between Europe and Africa.
Malta's hunting group said that it would take action against anyone found to be killing protected species.
"On good days for migration, when several hundred birds of prey pass through, the hunters are stirred into frenzy - desperate to shoot as many as possible, even within protected areas," said Grahame Madge, from the UK's Royal Society for the Protection of Birds (RSPB).
"To anyone who has not seen it for themselves, the scale of the slaughter beggars belief."
Mr Madge added that he believed that a "rogue element" of the island's hunters would "blast at anything that flies".
The two-week "raptor camp", organised by BirdLife Malta, invited birdwatchers from across Europe to monitor the autumn bird hunt on the island.
"Many observers have commented this is the worst season in recent years," said Andre Raine, BirdLife Malta's conservation manager.
"If BirdLife Malta can receive 17 birds of prey with confirmed gunshot injuries in eight days, then the actual number of protected birds that are being shot throughout the country must be very high."
Traditionally, the Maltese government has allowed hunters to shoot migratory quails and turtle doves for limited periods during the spring and autumn.
However, the spring season in 2007 was closed early after a flock of honey buzzards was shot dead.
Under the EU Birds Directive, member states are obliged to protect wild birds, and their eggs, nests and habitat.
Although the directive allows limited hunting of certain species, such as quails and turtle doves, during the autumn migration, spring shoots are outlawed.
Only a relatively small number of birds survive the overwinter period and complete the migration from Africa to breeding sites in Europe, which is why the directive has banned spring hunts.
In 2006, the European Commission began infringement proceedings against Malta for breaching the EU Birds Directive by allowing hunters to shoot migrating birds during the prohibited period.
However, the Maltese did not permit any shooting during this year's early season, angering some hunters.
Conservationists believe that some hunters could be using the autumn hunt season to vent their frustration and seek revenge.
Birdwatchers from across Europe attended the "raptor camp"
The Federation for Hunting and Conservation on Malta, also known as FKNK, said it condemned the illegal killing of birds.
In a statement responding to calls from a German campaign group for the hunting season to be closed early, secretary Lino Farrugia said: "FKNK repeats that it will disqualify any member who is convicted of any serious crime."
But he added that "collective punishment" was not the answer.
"On 10 May 2007, the Malta government imposed such a collective punishment by abruptly and unjustly closing the hunting season because it alleged that a 'massacre' of birds of prey by hunters took place the day before," Mr Farrugia wrote.
"To date, 500 days later, not a single shred of evidence has been brought to light, nor has a single person been [prosecuted] in court."
He went on to say that the FKNK was planning to take legal action against two of the group's activists for trespassing on private land.
BirdLife Malta called on the Maltese government to give the island's police force more resources to tackle the problem of illegal hunts.
"If our government does not stop seeing the hunting issue as an argument between two sides, the slaughter will continue," said the group's campaign co-ordinator Geoffrey Saliba.
"Illegal hunting across Malta is a national and international problem and a criminal act that... must be stopped now."